I. Technical Field
The present invention relates to a disk device for recording and reading information to or from a disk-shaped recording medium such as an optical disk or an opto-magnetic disk, as well as to a spindle motor that centers and rotates a disk, and a clamper that clamps a disk between itself and the spindle motor.
II. Description of the Related Art
With a conventional disk device, the most common method for attaching a disk to a rotating spindle motor is to clamp the disk between the spindle motor and a clamper chucked to the spindle motor. The disk is usually centered by fitting its center hole onto a boss of the spindle motor, in order that the head that writes and reads information to and from the rotating disk will stay as still as possible. However, because the clamper itself has weight, it is most often centered with respect to the spindle motor just as the disk is, in order to avoid vibration. A method for centering a clamper with respect to a spindle motor is disclosed in JP S56-114166(A), in which a convex component provided in the rotational center of a spindle motor mates with a concave component provided in the center of a clamper, and another such method is disclosed in JP H2-172055(A), in which a convex component provided in the center of a clamper mates with a concave component provided in the rotational center of a spindle motor.
However, the above-mentioned conventional structures are both designed so that there is a one-to-one correspondence in the centering between the spindle motor and the clamper. In recent years, meanwhile, the skyrocketing consumer demand for DVD recording and reproduction devices rather than video tape devices has led to a surge in the production of disk devices, and this popularity has also created the need for cost reductions. Nevertheless, with a conventional structure in which the spindle motor and the clamper are in a one-to-one correspondence as above, every time a new type of device is developed, a new spindle motor and clamper have to be designed and produced, which is a problem in that it impedes efforts at reducing cost.